Precision hammer



April 2, 1957 w. 1'. WARNER 2,787,179

PRECISION HAMMER Filed Sept. 16, 1955 2 Sheets-Sheet 1 INVENTOR WILLIAMT. WARNER AfiORNEYS April 1957 w. T. WARNER 2,787,179

PRECISION HAMMER Filed Se t. 16, 1955 2 Sheets-Sheet 2 INVENTOR WILLI AMT. WARNER ATTORNEYS PRECISION HAMMER William '1. Warner, Butte, Mont.

Application September 16, 1955, Serial No. 534,845

12 Claims. (Cl. 81--52.35)

This invention relates to hammering devices and more particularly to ahammer device having a blow whose power may be adjusted.

It is an object of this invention to provide a hammer in which thestrength of the hammer blow can be regulated from a very gentle tap to avery strong blow as desired.

It is a further object of this invention to provide a hammer devicewhich is adapted to interchangeably receive a variety of tools actedupon by the hammer, such as a chisel, punch, or designing tool.

It is a still further object of this invention to provide a hammerdevice which is angularly adjustable in such manner as to permit use ofthe hammer in confined locations having only a limited space.

it is still another object of this invention to provide a hammer devicein which the tool acted on by the hammer is securely held in place inthe hammer head, thereby minimizing danger of flying steel burrs fromthe tool and also permitting the operator to have one hand free to holdthe workpiece in place.

In achievement of these objectives, there is provided in accordance withan embodiment of this invention a hammer including a hammer head orhousing which supports a removable tool such as a chisel or the like. A.movable hammer member is longitudinally movable in the hammer housingand is biased into engagement with the tool by a strong spring memberdisposed within the hammer housing. The hammer member is connected to acable extending into a handle structure connected to the hammer housing.The handle structure is angularly adjustable with respect to the hammerhousing through a 90-degree angle to permit use of the hammer in variouslocations having a confined or restricted space. A hand grip lever iscarried by the handle structure and operates a pull arm having a firstpawl which cooperates with a ratcheted drawbar connected to the cablewhich is connected to the movable hammer member. The ratcheted drawbarmay be moved through a step-by-step movement by successive movements ofthe hand grip lever to correspondingly compress the spring in the hammerhousing.

A tension-holding second pawl is provided within the handle structure tohold the ratcheted drawbar at any position to which it may have beenadvanced by actuation of the hand grip lever. An adjustably movableeccentric means is engageable with the pull arm which engages theratcheted drawbar in such manner as to cause disengagement of the firstpawl with the ratcheted drawbar upon the completion of a predeterminedmovement of the operating handle. The eccentric member may be adjustedto a position at which the pull arm is disengaged from the drawbar justas the tension holding pawl engages the drawbar, thereby preventingreverse movement of the drawbar when the pull arm is released from thedrawbar. The eccentric may also be moved to other positions in which thefirst pawl is disengaged from the drawbar before the tension-holdingpawl engages the nited States PatentC 2,787,179 Patented Apr. 2, 1957"ice next succeeding tooth of the drawbar, thereby permitting adjustmentof the spring stress and of the resulting hammer blow for increments ofless than one ratchet tooth movement.

Further objects and advantages of the invention will become apparentfrom the following description taken in conjunction with theaccompanying drawings in which:

Fig. l is a sectional elevation view of a hammer in accordance with theinvention, the hammer being shown in inactivated position;

Fig. 2 is a view similar to Fig. 1 but showing the hammer in a cockedposition;

Fig. 2a is a detailed view of a portion of the hammer;

Fig. 3 is a side elevation view of the hammer corresponding to the viewshown in Fig. 1, with the operating mechanism within the handlestructure being shown in dotted outline;

Fig. 4 is a view in transverse section along line 44- of Fig. 3;

Fig. 5 is a view in transverse section along line 5-5 of Fig. 3; and

Fig. 6 is a perspective view of the tool-holding portion of the hammerdevice.

Referring now to the drawings, there is shown a hammer device generallyindicated at 10 including a hammer housing generally indicated at 12 anda handle structure generally indicated at 14 which is adjustably movablewith respect to hammer housing 12 through an angle of degrees to permituse of the hammer device in restricted locations.

Hammer housing 12 is a hollow generally cylindrical casing which servesas a housing for a hammer and a power spring. The hammer member is:generally indicated at 16 and includes an axially extending portion 18having a smaller diameter than the inner diameter of housing 12. Hammer16 also includes a base portion 29 integral with or connected to thelower end of portion 18 with respect to the view shown in the drawingand having a diameter just slightly less than the internal diameter ofhousing 12. A relatively heavy spiral power spring 22 is disposed withinhousing 12, one end of the spring abutting against an annular flange 24adjacent the upper end of the housing while the lower end or oppositeend of the spring abuts against the upper surface of base portion 20 ofhammer 16. A tool holder generally indicated at 2.6 is detachablyconnected to the lower or outer end of hammer housing 12 and includes agenerally cylindrical casing 28 which is detachably connected to thelower end of housing 12; by means of screws 30 or other suitablefastening means.

As will best be seen in the views of Figs. 1, 2 and 6, tool holder 28houses a pair of spaced lower and upper plate members 32 and 34. Lowerplate 32 is fixed with respect to casing 28 while upper plate: 34 isaxially movable within casing 28, the movement of upper plate 34 beinglimited by engagement with the lower edge of hammer housing 12. A spiralspring member 36 is disposed between the surfaces of plates .32 and 34and normally urges plate 34- away from plate 32 and toward the loweredge of hammer housing 12.

As best seen in the view of Fig. 6, each of the plates 32 and 34 isprovided with a slotted opening 38 and 49, respectively, having acentrally located circular enlargement. Upper plate 34 has a pair ofoppositely disposed concave recesses 42 which are disposedperpendicularly to the longitudinal axis of slot 41). A tool generallyindicated at 44 is adapted to be received and held by the plates 32 and34. Tool 44 may be of any suitable type, such as a hammer element, achisel, a punch, or a designing tool. Tool 44 has a generallycylindrical shank portion 46 which is received in the circular centralpor- .tion of the slotted apertures 33 and 4t and a pair of oppositelydisposed projecting ears 4% at its upper end which are adapted to bereceived through the similarly shaped elongated slotted portions of therespective apertures 3S and 4t). Adjacent its lower end, tool 44 isprovided with a circular rim portion 5%. The tool is inserted upwardlythrough the apertures 33 and 4t) and then rotated through an angle of 90degrees until cars 48 drop into the concave recesses 42 of upper plate34. The upper surface of rim 5% will then engage the underneath surfaceof lower plate 32. Spring 32? urges the upper plate 34 away from thelower fixed plate 32 thereby retaining tool member 44 positively inposition between plates 32 and 34. At the same time, tool 44 is free tomove downwardly with the freely movable upper plate 34 when hammermember 16 strikes against the upper end of tool 44 upon release of thehammer, as will be explained more fully hereinafter.

The handle structure 14 is formed of a pair of generally channel-shapedside members placed with their respective open sides in abuttingrelation. One end of the handle structure is disposed between a pair ofbracketlike extensions 54 at the upper end of hammer housing 12. Thehammer housing and handle structure are pivotally connected together bymeans of a pin or bolt member 52 which passes through extensions 54 andthrough handle 14. Handle structure 14 is freely movable on pin member52 and may be held in any desired adjusted position by means of aspring-biased pin 58 carried by spring arm 60 on handle 14. Pin 58engages any one of the holes 62 provided in the upper end of one of thebracket portions 54 to provide difierent angular adjustments of handle14 with respect to hammer housing 12.

A pulley 64 (Figs. 1 and 2) is supported for rotation by pin member 52which pivotally connects the handle 14 to the hammer housing 12. A cable66 is connected to the upper end of the hammer 16 and passes upwardlyover pulley 64 and into an axially extending passage 63 within thehandle structure 14. The end of cable 66 is connected to one end of adrawbar generally indicated at 70. Drawbar 70 includes a portion '72movable within the axial passage 68 and a second portion 74 which isoffset from the first portion 72 and which is movable axially Within achamber 76 disposed within the handle structure and communicating withthe elongated passage 68. Drawbar portion 72 is provided with ratchetteeth 76 while drawbar portion 74 is provided with ratchet teeth '78. Ahand-grip operating lever 80 is pivotally mounted at point 81 to theouter end of the handle structure. Lever 841 has a hand-grip portion 32disposed on the exterior of the handle structure, the opposite end oflever 80 extending upwardly into the interior of the handle structure.

An elongated pull arm 86 is positioned within chamber 76 and ispivotally connected at point 87 to the end of lever 80. A pawl member 88is carried at the opposite end of pull arm 86, pawl 88 being adapted toengage the ratchet teeth 76 of drawbar portion 72 to effect movement ofthe drawbar 7t) and of hammer 16. Pull arm 86 has a cam follower portion90 extending downwardly from its underneath surface in axially spacedrelation to pawl 88. Cam follower 90 is adapted to cooperate with aneccentric roller 92 to release pawl 3% from ratchet teeth 76. Eccentricroller 92 is carried at the lower end of a lever member 94 pivotallysupported by handle 14 and disposed for operation exteriorly of handle14. Lever 94 may be shifted about its pivotal axis 96 to change theposition of eccentric roller 92 relative to cam follower 90. A series ofdetent notches 95 (Fig. 2a) may be provided in the outer surface ofhandle 14 to positively position lever 94 in various angular positions.A bumper 75 of rubber or the like is provided to absorb the impact ofdrawbar 70 when the drawbar is released.

A lever member 98 is mounted for pivotal movement within chamber 76 andcarries a pawl member 1% which is spring-biased into engagement withratchet teeth '78 of the drawbar portion 74. Lever 98 may be raisedupwardly about its pivotal axis 99 to disengage pawl 10% with respect toratchet teeth '78 by means of an operating handle 102 disposed on theexterior of the handle 14 and rigidly connected to shaft 105 which inturn is rigidly connected to one end of an extension 1G4 disposed withinhandle 14. The opposite end of extension 1554 is pivotally connected at15117 to a vertical link 1% which in turn is pivotally connected atpoint 1% to lever 98 intermediate the length of lever 98. Shaft 1&5 ispivotally supported in the walls of handle 14 as best seen in Fig. 5,hence rotary movement of handle 162 is directly transmitted by shaft 1&5to the extension or crank 194. Thus, downward movement of lever 1Mcauses upward movement of link 106 and of lever 93 to thereby disengagepawl 100 from ratchet teeth '78.

The operation of the hammer device will now be described. With theproper tool 44 in position as shown in the views of Figs. 1, 2 and 3 andwith the parts initially occupying the positions shown in Fig. l,hand-grip portion 82 is pulled downwardly away from the handle structure14 from the position shown in Figs. 1 and 3 to the position shown inFig. 2, thereby rotating the inner end of lever tit) in acounterclockwise direction with respect to the views shown in thedrawings and causing pull arm 36 to advance to the left to engage thenearest tooth space to the left of the neutral or disengaged positionshown in Fig. l. The underneath surface of pull bar 86 is provided witha cutaway portion 116 which is so proportioned with respect to eccentricroller 92 as to permit pawl 88 to drop downwardly into the first toothspace to the left of the disengaged position of the pawl shown inFig. 1. The linear movement imparted to pull arm 86 by rotation ofhand-grip portion 32 from the position of Fig. 1 in a counterclockwisedirection to the position of Fig. 2 is equal to the tooth pitch of theteeth 76. With pawl 88 engaged with a tooth '76, the operating handle isthen moved back in a clockwise direction to the position shown in Fig.1, causing pull arm 86 to pull drawbar 70 forwardly by a predetermineddistance, such as the pitch of one of the teeth 76. The distance whichdrawbar 7G is moved forwardly depends on the position of eccentricroller 92 with respect to cam follower 90. As operating lever 80 reachesthe end of its clockwise movement, cam follower 94 on the underneathsurface of pull arm 86 engages eccentric roller 92 and raises pull arm86 upwardly to the position shown in Fig. 1, causing pawl 88 to becomedisengaged from the tooth 76 with which it was engaged.

With the eccentric roller 92 in the position shown in Figs. 1, 2 and 3,pawl 88 is raised out of engagement with ratchet tooth 76 just as pawl10% drops into engage ment with one of the teeth 78. Hence, release ofpawl 38 from a tooth 76 will not cause release of the stress on spring22 since the drawbar will be held in its new position due to theengagement of pawl 1% with a tooth 78.

in order to provide still greater stress on spring 22 with consequentgreater hammering force by hammer 16 when the spring force is finallyreleased, the drawbar it? may be actuated still further to the rightwith respect to the view shown in the drawings by successive actuationsof the operating lever 80. Thus, hand-grip portion d2 of. lever so maybe again moved downwardly to the position shown in Fig. 2 to cause pawl33 to engage the next tooth 76, and then moved upwardly again to movedrawbar 76 to the right until the cam follower is engaged by eccentric92 to disengage pawl 33 from the second tooth. Pawl will drop into athird ratchet tooth 78 to hold the drawbar 70 in its next actuatedposition. This proces may be repeated a number of times corresponding tothe number of ratchet teeth 76.

For example, in the view shown in Fig. 2, the operating lever tilt isshown in the middle of its fourth stroke, the hand-grip portion 32having been successively actuated four times to finally engage thefourth tooth. As shown in Fig. 2, lever 80 is ready to begin itsclockwise movement to move the pull arm 86 to the right and, by the timethat the cam follower 96 reaches eccentric 92, pawl 100 will drop behindthe next ratchet tooth 78 to hold the hammer 16 in its cocked position.

When operating lever 80 has been actuated a number of timescorresponding to the desired degree of stress on spring 22, lever 162 ismanually pushed downwardly about its pivot point 105 to raise verticallink 106 upwardly and to thereby raise pawl 100 out of the path ofmovement of ratchet teeth 78. This releasing movement of lever m2 ispreferably done during the last pulling movement on drawbar "ill whilepawl 88 is engaged with one of the ratchet teeth 76. This permitseccentric roller 92 to release pawl 88 from ratchet 76 on the finalforward pull on drawbar 7%, thereby releasing the drawbar and permittingthe stored energy in spring 22 to drive hammer l6 downwardly intoengagement with tool 44, the degree of force of the blow of hammer 16 ontool 44 depending upon the degree of stress placed in spring 22.

A further feature of the construction is the fact that lever 94 can berotated about its pivotal axis 96 to advance the crest of eccentric 92with respect to cam follower 90 to cause a disengagement of pawl 88 fromratchet tooth 76 before pawl 100 has an opportunity to drop into thenext succeeding tooth space. Thi feature may be used to adjust thestrength of the blow of hammer 16 for increments of stress on spring 22corresponding to move ments of less than one tooth space of drawbar 70.Thus, for example, assume that pawl 83 and pull arm 86 are in theposition shown in Fig. l in which spring 22 is completely discharged. Ifeccentric 92 is permitted to stay in the position shown in Fig. l, asingle actuation of the operating lever 80 will cause spring 22 to bestressed an amount equal to a one-tooth movement of drawbar 70, sincepawl iii-l will drop into a ratchet tooth 78 upon the completion of onecycle of movement of operating lever 89. However, under certaincircumstances, it may be desirable to have spring 22 stressed for anamount even less than one tooth space. In this case, operating handle 94is rotated in a clockwise direction with respect to the view shown inthe drawings to advance eccentric 92 in such manner that pawl 88 israised out of engagement with ratchet tooth 76 before pawl 1% can moveinto engagement with the second ratchet tooth 73. By rotation of lever94 to several successive positions, the spring 22 may be discharged atseveral difierent predetermined stresses less than the stresscorresponding to a one-tooth movement of drawbar 75). This permitsseveral different adjustments of the impact of hammer 16 within the lowrange of spring stress to permit variation of the impact of hammer in inthis range.

The adjustment feature of eccentric 92 just described may also be usedto obtain spring stresses corresponding to movements or drawbar 7s forone or more tooth spaces plus a fraction of another tooth space, tothereby provide a precise adjustment of the hammer blow. For example,drawbar 7%) may be advanced for three teeth of ratchet 72 bystep-by-step operation previously described, with lever 94 in theposition shownin Figs. 1-3. With lever 94 in this position, aspreviously described, pawl ltlil always drops into a tooth space ofratchet 78 just as pawl 88 is disengaged from ratchet 7s. Aftercompleting three stepby-step movements in the manner just described,lever 9 may then be rotated to a position in which cam follower 9t)engages eccentric 92 sooner than in the previous operations; say, forexample, after a movement of onehalf tooth space. Lever 80 is actuatedin the usual manner to cause pawl 88 to engage a tooth 76. With pawl 88in engagement with a tooth 76, lever 102 is then actuated 6 to raisepawl 10%} out of Operating lever 80 is actuated to advance drawbar 76until cam follower 99 engages eccentric 92. On this operation,

. cam follower 90 will engage eccentric 92 earlier than in the previousoperations, in the example given, at an additional increment of stresscorresponding to a movement of one-half tooth pitch. Upon engagement ofcam follower with eccentric 92, pawl 88 will be disengaged from ratchet76 and the stored energy of spring 22 will drive hammer 16 downwardlyinto engagement with tool 44. In the example just given, the stress on.spring 22 and the corresponding force on hammer 16 will be thatcorresponding to a movement of three and one-half teeth of ratchet 76.

It can be seen from the foregoing that there is provided in accordancewith this invention a precision hammer which has great utility since itpermits the adjustment of a hammer blow through a wide range from a verylight tap to a very strong blow by its regulating mech anism. Also, thepivoted construction of the handle with respect to the hammer housingpermits the hammer to be adjusted to many different angular positions tofacilitate working under varying conditions and in confined spaces.Furthermore, the tool holder arrangement permits easy replacement oftools which are acted upon by the hammer and permits interchangeable useof tools required for specific jobs, such as a hammer, chisel, punch, ordesigning tool. Furthermore, the tool is securely held in place withrespect to the hammer by the tool holder in such mam1er that theoperator has one hand free to hold the workpiece.

While there has been shown and described a particular embodiment or" theinvention, it will be obvious to those skilled in the art that variouschanges and modifications may be made therein without departing from theinvention and, therefore, it is aimed to cover all such changes andmodifications as fall within the true spirit: and scope of theinvention.

What I claim as my invention is:

1. A hammer device comprising a hammer member, spring means urging saidhammer member toward hammering position, first ratchet means for movingsaid hammer member in graduated steps against said spring to storeenergy in said spring, second ratchet means for holding said hammermember against said spring at each predetermined step of increasedspring stress, and means for releasing said second ratchet means topermit the stored energy in said spring to move said hammer member witha hammering action.

2. A hammer device comprising a hammer member, spring means for urgingsaid hammer member into hammering position, means for moving said hammermember against said spring in graduated steps to store graduated amountsof energy in said spring, means for applying stress to said spring inincrements of less than one of said predetermined steps, and means forreleasing said hammer member to permit the stored energy in said springto provide a hammering action.

3. A hammer device comprising a housing, a hammer member movablein saidhousing, a spring in said housing engaging said hammer member to urgesaid hammer member to hammering position, first ratchet means for movingsaid hammer member against said spring in graduated steps to storeenergy in said spring in accordance with said graduated steps, secondratchet means for holding said hammer member against said spring at eachstep of spring stress a tool member supported by said housing in thepath of movement of said hammer member, and means for releasing saidsecond ratchet means to permit the stored energy in said spring to forcesaid hammer member into engagement with said tool member.

4. A hammering device comprising a hammer member, a spring memberengageable with said hammer mem ber to move said hammer member intohammering position, a ratchet arm connected to said hammer member,

engagement with ratchet 78.

means for moving said ratchet arm in predetermined increments tocorrespondingly stress said spring in predetermined steps, means forholding said ratchet arm in the successive positions to which it ismoved, and means for releasing said ratchet arm and said hammer.

5. Ahammer device comprising a hammer membe a spring engaging saidhammer member and urging said hammer member into hammering position, adrawbar connected to said hammer member, first ratchet means for movingsaid drawbar and said hammer member in graduated steps to stress saidspring in predetermined increments, second ratchet means for holdingsaid drawbar in a given step to which it is moved, and means forreleasing said drawbar to permit said spring to move said hammer intohammering position.

6. A hammer device comprising a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position, adraw bar connected to said hammer member, said drawbar being movable tomove said hammer member against said spring to store energy in saidspring, said drawbar including a ratchet means, a first pawl memberengageable with said ratchet means, means for moving said first pawlmember out of engagement with said ratchet means at the end of apredetermined movement of said drawbar, a second pawl member engageablewith said ratchet means, said second pawl member being engageable withsaid ratchet means to hold said drawbar in a pretermined position afterthe release of said first pawl member, and means for releasing saidsecond pawl member from said ratchet means to permit said spring to movesaid hammer member into hammering position.

7. A hammer device comprising 'a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position, adrawbar connected to said hammer member, said drawbar being movable tomove said hammer member against said spring to store energy in saidspring, said drawbar including a first and a second ratchet portion, apull arm having a first pawl member engageable with said first ratchetportion, an operating handle connected to said pull arm, meansengageable with said pull arm at the end of a predetermined operatingstroke to move said first pawl member out of engagement with said firstratchet portion, a second pawl member engageable with said secondratchet portion, means for causing said second pawl memher to engagesaid second ratchet portion to hold said drawbar in a predeterminedposition after the release of said first pawl member from said firstratchet portion, and means for releasing said second pawl member fromsaid second ratchet portion to permit said spring to move said hammermember into hammering position.

8. A hammer device comprising a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position, aratchet means connected to said hammer member, said ratchet means beingmovable to move said hammer member against said spring to store energyin said spring, pawl means engageable with said ratchet means to effectmove ment of said hammer member, means for moving said pawl cans out ofengagement with said ratchet means at the end of a predeterminedmovement of said ratchet means, and means for adjusting the preterminedmovement of said ratchet means required for disengagement of said pawlmeans. i

9. A hammer device comprising a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position,drawbar connected to said hammer member, said drawbar being movable tomove said hammer member against said spring to store energy in saidspring, said drawbar including a ratchet means, a pawl member engageablewith said ratchet means to effect movement of said drawbar, means formoving said pawl member out of engagement with said ratchet means at theend of a predetermined movement of said drawbar, and means for adjustingthe predetermined movement of said drawbar required for disengagement ofsaid pawl member from said ratchet means.

10. A hammer device comprising a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position, adrawbar connected to said hammer member, said drawbar being movable instepped increments to move said hammer member against said spring tostore energy in said spring, said drawbar including a ratchet means, anoperating lever pivotally mounted on said hammer device, a pull armconnected to said operating lever, a pawl member carried by said pullarm and engageable with said ratchet means to move said drawbar, cammeans engageable with said pull arm for moving said pawl member out ofengagement with said ratchet means at the end of a predeterminedmovement of said drawbar, and means for adjusting the predeterminedmovement of said drawbar required for disengagement of said pawl memberfrom said ratchet means.

11. A hammer device comprising a hammer member, a spring engaging saidhammer member and urging said hammer member into hammering position, adrawbar connected to said hammer member, said drawbar being movable instepped increments to move said hammer member against said spring tostore energy in said spring, said drawbar including a ratchet means, anoperating lever pivotally mounted on said hammer device, a pull armconnected to said operating lever, a pawl carried by said pull arm andengageable with said ratchet means, said operating lever being actuablethrough a forward and reverse movement about its pivot point to engagesaid pawl with tooth of said ratchet means and to move said drawbarthrough a predetermined movement against said spring, cam meansengageable with said pull arm for moving said pawl member out ofengagement with said ratchet means at the end of a predeterminedmovement of said drawbar, and means for adjusting the predeterminedmovement of said drawbar required for disengagement of said pawl memberfrom said ratchet means.

12. A hammer device comprising a housing, a hammer member carried by andmovable in said housing, a spring carried by said housing and urgingsaid hammer member into hammering position, a handle member connected tosaid housing and angularly adjustable with respect there to, a ratchetmeans carried by said handle member, a cable means connecting saidratchet means to said hammer member, means for imparting a steppedmovement to said ratchet means to apply increments of stress to saidspring member whereby the blow of said hammer member may be adjusted toa desired value, and means for releasing said ratchet means to therebyrelease said hammer member.

References Cited in the file of this patent UNITED STATES PATENTS690,945 Gray Jan. 14, 1902 2,455,577 Hager Dec. 7, 1948 FOREIGN PATENTS453,203 Italy Nov. 23, 1949

